I have ducting in diameter of 355mm or 14 inch. I want to seal my room, so how to I close the air gaps where the ducting goes through my drywall?
I used galvanized metal sheet ducting parts to go through the drywall and then connected sonoduct hoses. Sometimes the gaps between the glavanized form parts are only smal, so I guess I just can use acrylic or silicone for that.
But some times the gaps are a bit bigger e.g. 1 inch. How do I seal that? I also have joint compund here, but I guess that is maybe to rigid and doesnt connect well to the galvanized metal sheet parts? Or should I use silicone with some filling materials extra?
Or how about that stuff: https://www.greatstuff.dupont.com/how-to-air-seal-hvac-ducts-and-penetrations.html
Is that good?